Research And Implementation Of Adaptive Prospective Interpolation Method For High Speed Machining Based On The Cubic Polynomial Model

High speed CNC machining system plays an important role in modern manufacturing industry,feed rate and machining precision are the key indicators to evaluate the performance of the system.During the process of high speed machining,the existence of the speed change point causes the mutation of feed rate and feed direction,which seriously affects the machining precision.Therefore,the look-ahead interpolation technique has been widely used in CNC system and effectively solved the problem.In order to find the speed change point in the NC machining,pass through the interpolation point smoothly and reduce vibration caused by speed mutations,an adaptive cubic polynomial look-ahead interpolation algorithm based on NURBS curve interpolation was proposed and a general model was established.Firstly,the speed mutation points was found out by summing up the curvature variation rules and the correlation calculation of the NURBS curve.Secondly,the curve was divided into several segments,and the local optimal solution based on the chord error and cubic polynomial acceleration and deceleration was proposed.Thirdly,by analyzing the nested relation of the velocity at the mutation point,the computational method of the prospective distance was given.Finally,according to the requirements of the computation of the deceleration point position,the reverse interpolation was put forward in the prospective range,and the real-time optimization model of feed rate was proposed.In this paper,through the simulation of the speed adaptive cubic polynomial interpolation algorithm using two kinds of different trajectory curves,and compared with the performance of the S based and traditional cubic polynomial acceleration and deceleration algorithm,the results show that the proposed algorithm can reduce the running time of the S model by 1.62%,the maximum chord error is reduced by 6.77‰ compared with the traditional cubic polynomial acceleration and deceleration algorithm.In addition,the algorithm has been simulated in the RunJin CNC machining platform,and its single interpolation time is 0.061 ms,which can meet the requirements of the maximum interpolation time 1ms.